Rotary drill bit



May 25, 1943. A. w. KAMMERER ROTARY DRILL BIT Filed Aug. 12, 1941 fig.2.

I N V EN TOR. ARK/ E2 T/l fkllMMb-eee,

BY I

ATTORNEY.

its required diameter.

Patented May 25,

.. norm! mun. m

mm- W.Kammercr,1 ullerton, Calif.

"npplicatlon August 12,

10 Claims.

This invention relates to earth boring tools, and more particularly todrilling bits used in the rotary drilling of oil, gas and similar wells.

The present case is a continuation-in-part of my prior applicationentitled "Well drilling bits," Serial No. 358,946, filed September 30,1940.

An object of the present invention is to obtain the discharge ofdrilling fluid directly upon the bottom of the bore hole being producedby a drill bit of the combined roller and drag cutter type, for thepurpose of effectively removing cuttings from the well bore andincreasing the rate of penetration of the cutting elements into theformation.

A further object of the invention is to provide a drill bit of thecombined roller and drag outter type which is capable of projecting astream of drillingfluid directly upon the bottom of the bore hole beingproduced, this stream'also beingefi'ective to maintain the drag cutterand roller cutter elements of the bit free from cuttings.

Yet a further object of the inventoin is to provide a combined rollerand drag cutter type of rotary drill bit of stronger and sturdierconstruction than heretofore available.

This invention possesses many other advantages and has other objectsthat will become apparent from a consideration of the embodiment shownin the drawing accompanying and forming part of the presentspecification. This form will now be described in detail to illustratethe general principles of the invention, but it is to be undertsood thatsuch detailed description is not to be taken in a limiting sense, sincethe inven tion is best defined by the claims appended hereto.

Referring to the drawing:

Figure 1 is an eievational view of a drill bit, parts being removed forpurposes of clarity, and other portions being shown in section;

Figure 2 is a generally longitudinal section taken along the line 2"2 ofFigure 1; and

Figure 3 is a plan view as seen from the bottom of Figure 1.

As disclosed in the drawing, the drill bit includes amain body or shanki having the usual threaded tapered pin ii at its upper end forattaching the bit to a tubular string of drill pipe (not shown), bymeans of which the drill bit is rotatable from the surface of the borehole, in a well-known manner. Depending from the main body i0 is a pairof legs l2, l2 rotatably carrying side or gauge toothed cutters i3, 11.whose purpose is to remove the outer portions of formation material andmaintain the hole to These cutters are each 1941;: Serial No. 408,492

- rotatably mounted on a suitable bearing support il-fl xed to a leg I!and inclined inwardly and downwardly toward the axis of the bit. Thecutters l3,. II are preferably of such length as to position the innerends of their uppermost teeth closely adjacent one another, to permittheir cleansing, as described below.

The formation material within the annulus a: cut by the side rollercutters i3 is removed by cutters of the drag or blade type. This dragassembly i5 consists of outer drag cutters i6, its. and inner dragcutters i1, Ila. disposed at an angle to the former and leading them asregards the direction of rotation of the drill bit. The drag assembly ispreferably formed of two main parts, each consisting of an outer dragcutter It or its and an inner, leading drag cutter H or l'la connectedto the former by a web ill or No.

The outer drag cutters i6, iia are suitably attached to depending legsl9, l9 disposed between the legs l2, I2 supporting the roller cuttersit, as by welding material 20. These cutters i6, l6a may extend alongtheir supporting legs l9 for disposition substantially at right anglesto the axes of the roller cutters i3. It is to be understood, howeverthat this angle can be varied somewhat, if desired, depending upon theparticular portion of each leg l9 to which the outer cutter It or I60.is attached. I

The outer drag cutters It, I to remove an an- .nulus y of formationmaterial from the bottom of the hole within the path a: cut by theroller cutters l3, whereas the inner drag cutters l1, I'Ia removeformation material 2 within the path 1/ traced by the outer cutters. Thebottom cutting edges lib ot the outer cutters are preferably disposedabove the bottommost cutter teeth l3a or the side roller cutters, whilethe bottom cutting edges ill) of the inner drag cutters are preferablydisposed above that lib of the outer drag outters i8, lid, to enhancethe drilling effectiveness of the bit and the production of a verticalhole, as more particularly brought out and claimed in my UnitedStatesrPatent No. 2,244,537, patented June 3, 1941.

It is to be noted that a space 3 remains between the upper inner edgesof the outer drag cutters I6, I61: to allow positioning of the uppermostteeth I31) of the side roller cutters i3 ad jacent one another. Theinner drag cutters l1, Ila. fastened to the outer cutters I6, I61: bythe respective connecting webs l8, l8a, are disposed on opposite sidesor a central plane ofthe drill bit, which plane lies generally along theaxes of the roller cutters it. These inner drag cutters aresubstantially parallel to one another, being spaced apart by a smalldistance 6, resulting in the tendency for a core of material to remainas the drill bit rotates that is of too small a size to sustain itselfduring operation of the drill bit on the bottom oi the hole. breaks offand cannot impede effective and emcient operation of the drilling toolin the well bore.

Unification of the entire bit construction is completed by welding theouter upper portions" 2| of each inner drag cutter I1, I10. to thestationary bearing support ll of one oi the roller cutters l3, andattaching its inner portion to the opposed stationary bearing throughthe medium of a transverse arm 22 welded or otherwise se cured to bothof these members l4 and I1, Ila. Inasmuch as the stationary bearingsupports l4 carying the side cutters l3 and the outer drag cutters l6,Ilia are welded to their respective depending legs l2, IS, the weldingof the generally parallel, spaced, inner drag cutters I I, Fla and theirarms 22 to the opposed bearing supports i4 integrates and unifies theentire bit construction.

The bearing supports I4 are made functionally integral with one anotherby the inner drag cutters l1, lla and their arms 22, which, in effect,provide two spaced braces therebetween. Moreover, the outer drag cuttersI6, lGa are given material support in addition to that afforded by theirattached legs by the integrating of each inner drag cutter I! or Ila andits associated arm 22 to the bearing supports [4. Still further supportis given to the outer and inner drag cutters on each side of the bit,since the bearing supports it themselves serve as a means fortransmitting loads from one set of drag cutters l6, I! through the otherset I611, I111 to the drag cutter leg l9 on the other side of the bit.strong and sturdy combined roller and drag cutter bit construction hasbeen provided, permitting operation without failure under heavy drillingweights and at high rotative speeds.

The side roller cutters l3 and outer drag cutters l6, Ilia aremaintained free from detritus by fluid issuing from suitable nozzles 23communicating with a fluid chamber 24 merging into a fluid passage 25extending through the bit body l and upper threaded pin ii. A centralnozzle 26 is provided in the bit body to receive fluid from the fiuidchamber 24 and discharge it downwardly through the spaces between theouter drag cutters l6, Mia and the space d between the inner dragcutters i'la directly onto the bottom of the bore hole, from where thecuttings are flushed outwardly towards the side of the bit for upwardpassage therearound and along the exterior of the drilling string to thesurface of the well bore. As was stated above, the core of formationmaterial at the bottom of the hole that might tend to form as a resultof spacing the inner drag cutters from each other is eliminatedautomatically during operation of the bit since it is of too smalldimension to sustain itself, and therefore, readily disintegrates. Thisaction is assisted by the hydraulic force of the fluid jet issuing fromthe central nozzle 26 which not only acts directly upon the bottom ofthe hole to maintain it free from cuttings, but also acts upon thecutting faces of the inner drag cutters l1, l'la to keep them clean andavailable for efilcient penetra- It is, therefore, apparent that a,

This core readily tion into the hole bottom. The central nozzle 28 canalso accomplish a further purpose by directing fluid for action upon theinner portions l3b of the side cutter teeth as they reach theiruppermost positions, to clean them of any adherent cuttings and placethem in condition for maximum penetration into the formation at thebottom of the bore hole.

It is accordingly apparent that a rotary drill bit has been providedwhich is not only of sturdier construction than tools of similar typesheretofore available, but which also assures the maintenance of the bitand bottom of the hole free from cuttings or other adherent matter withgreater facility.

I claim:

1. A drill bit, including a main body, bearing supporting means carriedby 'said body. side roller cutters rotatably mounted on said bearingsupporting means, a drag assembly secured to said main body and havinginner and outer cutters disposed at an angle to each other, said innercutters lying in separate planes that are spaced from each other, andmeans for securing said inner cutters to said bearing supporting means.I

2. A drill bit, including a main body having a pair of depending legs,bearing supporting means extending inwardly from said legs, side rollercutters rotatable on said bearing supporting means, a second pair oflegs depending from said body between said first-mentioned pair, a dragassembly secured to said second pair of legs and having inner and outercutters disposed at an angle to each other, said inner cutters beingarranged in spaced, generally parallel relation on opposite sides of acentral axial plane of the bit; and means for securing said innercutters to said bearing supporting means. a

3. A drill bit, including a main body, bearing supporting means carriedby said body, roller cutters rotatably mounted on said bearingsupporting means, spaced drag cutters extending between said main bodyand bearing supporting means and secured directly to both said main bodyand said bearing supporting means, and means for projecting fluidthrough the space between said drag cutter directly onto the bottom ofthe bore hole being produced by the drill bit.

4. A drill bit, including a main body, bearing supporting means carriedby said body, roller cutters rotatably mounted on said bearingsupporting means, and spaced drag cutters securing said bearingsuporting means together, said drag cutters lying in separate planesthat are spaced from each other so as to provide a plurality of spacedbraces between said bearing supporting means.

5. A drill bit, including a main body having a pair oi-depending legs,bearing supporting means extending inwardly from said legs, side rollercutters rotatable on said bearing supporting means, and a pair of dragcutters extending between and securing said bearing supporting meanstogether, said drag cutters lying in spaced, generally parallel relationon opposite sides of a central axial plane of the bit so as to provide apair of spaced braces between said bearing supporting means.

6. A drill bit as defined in claim 4, including nozzle means fordirecting drilling fluid through the space between said drag cuttersdirectly upon the bottom of a bore hole being produced. 7. A drill bitas defined in claim 5, including centrally located nozzle means fordirecting drilling fluid through the space between said drag cuttersdirectly upon the bottom of a bore hole being produced.

,8. A drill bit, including a main body having a pair of depending legs,opposed bearing supports extending inwardly and downwardly from saidlegs, side roller cutters rotatable on said bearing supports with theirupper portions adjacent one another, a pair of drag cutters extendingbetween and securing said bearing supports together, said drag cutterslying in spaced, generally parallel relation on opposite sides of acentral axial plane of the bit, and nozzle means for directing drillingfluid'onto said adjacent side cutter portions and through the spacebetween said drag cutters directly upon the bottom of a bore hole beingproduced.

9. A drill bit, including a main body having a pair of depending legs,opposed bearing supports extending inwardly from said legs, a rollercutter rotatably mounted on each bearing support, a second pair of legsdepending from said body between said first-mentioned pair, a dragassembly secured to said second pair of legs and having inner and outercutters disposed at an angle to each other, said inner cutters beingarranged in spaced, generally parallel relation on opposite sides of acentral axial plane of the bit, means for securing said inner cutters tosaid bearing supports, and a nozzle for projecting drilling fluidthrough the space between said inner cutters directly upon the bottom ofa bore hole being produced.

10. A drill bit, including a main body having a pair of depending legs,opposed, inclined bearing supports extending inwardly and downwardlyfrom said legs, a roller cutter rotatably mounted on each bearingsupport, drag cutters secured to said main body and lying generally atright angles to the axes of said roller cutters, said drag cutters beingspaced from one another to permit the upper, inner portions of saidroller cuttersto lie closely adjacent one another.

ARCHER W. KAMMERER.

